VIP’s Disinhibitory Role in Attentional Modulation of Visual Neurons

Published on November 4, 2022

Imagine you’re at a crowded marketplace, trying to focus on a specific vendor. In the brain, this selective attention process enhances the firing rate of border ownership selective (BOS) neurons that help us distinguish objects from their background. However, an interesting paradox occurs: as these BOS neurons fire more, their synchrony decreases. Scientists have now discovered that a disinhibitory circuit involving vasoactive intestinal polypeptide (VIP) and somatostatin (SOM) interneurons underlies this phenomenon. Just like a skilled orchestra conductor coordinating musicians, VIP interneurons suppress SOM interneuron responses and activate BOS neurons, allowing attention to selectively amplify their firing. By influencing the inhibitory network, VIP interneurons play a critical role in attentional modulation of neurons in visual areas. These findings not only provide insights into the neural mechanisms of selective attention but also highlight the importance of inhibitory circuits in shaping our perception. Dive into the fascinating research to uncover how VIP’s role in disinhibition influences our visual experience!

The activity of border ownership selective (BOS) neurons in intermediate-level visual areas indicates which side of a contour owns a border relative to its classical receptive field and provides a fundamental component of figure-ground segregation. A physiological study reported that selective attention facilitates the activity of BOS neurons with a consistent border ownership preference, defined as two neurons tuned to respond to the same visual object. However, spike synchrony between this pair is significantly suppressed by selective attention. These neurophysiological findings are derived from a biologically-plausible microcircuit model consisting of spiking neurons including two subtypes of inhibitory interneurons, somatostatin (SOM) and vasoactive intestinal polypeptide (VIP) interneurons, and excitatory BOS model neurons. In our proposed model, BOS neurons and SOM interneurons cooperate and interact with each other. VIP interneurons not only suppress SOM interneuron responses but also are activated by feedback signals mediating selective attention, which leads to disinhibition of BOS neurons when they are directing selective attention toward an object. Our results suggest that disinhibition arising from the synaptic connections from VIP to SOM interneurons plays a critical role in attentional modulation of neurons in intermediate-level visual areas.

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